I'll second the JHH kits. Their sabre is a well known great flyer. DCU also makes a Mig15 right around the same size.
If you can afford it, buy yourself a brand new OS46VX and the fan and pipe to go with it. If not, find the older OS46VRDF, that's a good one, too. The K&B's are okay, but don't get stuck with one of the really old ones floating around. You should contact Larry Wolfe of JHH, he is the undisputed guru of 45 fans and will really help you out.